Lamp exhaust tube bending apparatus



April 18, 1950 G. s. QUINN ET AL 2,504,938

LAMP EXHAUST TUBE BENDING APPARATUS Filed Feb. 27, 1947 2 Sheets-Sheet 1 INVENTORS 6545410 6.@0//V/V A/VD 61/1 67? Mfi/V/V ATTORNEY Afifil 18, 1950 M T AL 2,504,938

LAMP EXHAUST TUBE BENDING APPARATUS Filed Feb. 27, 1947 2 Sheet-Sheet 2 INVENTORS- 629mm SQM/V/V 440 51/145? MAW/V ATTORNEY Patented Apr. 18, 950

- ssachusetts f a niatinnretmrazv, 194:; sesame. 731,332;

invention relates to electric larnps= discharge devices and more p'ar'ticularl'yto neetrio lamps and discharge devices which are proith a'glass'tubu-lation for; evacuation and V g purposes' during the manu-facturing-' thereof' This invention is particularly adtan-' tageous in the manufacturing of circular lamps; such asoircular fluorescentlamps.

Ah ob "ctofjthis invention is to provide 3.131.531 ending a glass exhaust tube.

A other object isto provide apparatus for" bending:a glassexhausttubeduringtheprocessing*-' olff' he'jdeviceto' which itjiS' connected;

further object'is; to' provide apparatus for bending aglas's exhaust tube of a circular lamp duri'ngf the manufacturing of the a i H Further" objects, advantages, and features; will beiapparerit from thefoll'owi'ngdescription when readin' conjunction with the accompanying drawings-in' which; 7

Figure 1 is a perspective view ofa lamp tube bendin'g 'appa'ratu's and the exhausttube'b'endin'g' mechanism; of our invention, showing therelative disposition of 'the several partstherepf before the lamp tube and exhaustjtube-bending opera-- tions:

Figure 21s a perspective view off'thei apparatus" andfmeehanismof Figure f showing"th'e;relative' disposition of the several; parts: thereof" after the lain-ptiibeandexhaust"tube,bendingoperations:

Figure 3 is an enlarged perspectiye view-of the exhaust?"- tube bending mechanism shown. partly im-section; v

The manufacturing of a circular fluorescent lain-p pre'sents many 'problemswhich are notcom fronted in the manufacturing of conventional lin ntypfelamps} The'exhausfltube which, durs in'g: part of th'edampmanufacturing; process; ex te nds froin one-end of the lamp; is a source" of one or these problems. This is especially true" when the'lainp' electrodesaresealed in the ends ofthe'i'lamp before'the'lamp is formediinto the finally desired shape.

The; exhaust" tube" bending apparatus of our invention is particularly adaptable f for use with the? tube" fojrining, apparatus shown in the co- 1 Quinn, serial Number svegi-safiiedt une 6; now-abandonedf However; its adapt aiiility to" otheriormsand types of apparatus will" pending application of Ralph B; Thomas and;

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ventibn may be -employee: Thisla'rnp tuhe form s5 posedi 2 Claims; (c1. 49-'22f) 2 ing apparatus provides'a means whereby'ahelir' cally formed unit of glass tubing; which has had its innerwal'l coated with luminescent material and'electrodes sealed at eachend thereof; may be shaped into. its final circularv form'pricrto evacuation. The lamp 'tube'unit is a single turn section cutfrom a helix; of'glass tubingil'wi a space between the endsthereof"preferably -'slightly** lessthan the finally requiredspacing; The piteh of'thehelix is predetermined so that the endsof" each. unit cut therefrom will be offsetfront: each other the desired amount, Theinnenwall" f'each unit'jiscoated' with luminescent material and electrode mounts are sealedineach:' 'end'f thereof. At least one of these mounts is" pro-- vid'ed with an exhaust tube through which the sealed device may be evacuated.

As maybe seen in Figurel; theexhaust tuh'e" I, which extends from an end' 2 offthelamp, tube 3; liesin; the path through which the other" endof the" tube 3 will travel during. the lainp-"tuhe forming operation. The exhaust tub'e- I' may be bent perpendicular to the axis. of' the helix by hand bending the exhaust tuloe I before the'lamp tube 3 is mounted on the lamp tubebendingiig 4. Howevenywe have foundthismethodto be impractical and unsatisfactory; Accordinglyq;w therefore; we have providedmechanical' means" for effecting the bending ofthe exhaust" tube" 51 durina the lamp tube forming operation;

Bending of the exhaust tube l'is accomplishedby; means" of a gravity-operated mechanism: mounted on. the jig 4. This mechanismwhich isshowzi moreiini detail; in Figure 3, comprises a: cradletfi in which the exhaust" tube i is disposed, mounted on a. pivot shaftfi' which may be dis? posedat right angles to the top, plane of the" jig; 4; an arm T attachedjat' one" end thereof to th'e pivotshaitfi, and; a weight't attached to theothenend'of' the arm T. The pivot shaftfi is mounted in suitable low friction bearings to allow' free moven'ient ofthe shaft in translating'theflver'ti cal component of the weight 8 into angularlmo" tion' of. the cradle in which the'exhaust tiubetisIdis- The manner'in which this operation.. is performed is described more fully below:

Theljig t comprises an annular plate; 12;}, an; eccentric stop I c andja clamping arm H 'rnounted'i on the periphery thereof, a fixed. stops, on the" face of the plate l2 and against whi hthe end! .TE 7 OFFICE proper disposition of the ends of the lamp tube 3 upon completion of the tube forming operation. The helically formed unit of glass tubing or lamp tube 3, as shown in Figure 1 is positioned on the jig 4 with the end 2 thereof abutting astop 9 on the top face of the jig. The tube 3 is then centered with reference to a line running through the center of the circle which it defines and the center of the space between the ends of the tube as finally formed. An eccentric stop i0 mounted on the periphery of the jig is then adjusted to cause it to engage the tube 3 and a clamping arm Ii, pivotally mounted on the eccentric stop it, is swung in to lock the tube in position.

The V-block I3 is positioned on the end 2 of the lamp tube 3 and the V-block i4 is pos tioned on the end IQ of the lamp tube. In order to prevent the weight of the V-block 13 from distorting the end 2 of the lamp tube 3 during the tube forming operation a means is provided for relieving .the tube 3 of this weight. This means comprises an elongated screw 20 which extends through the V-block l3 into a post l5, and a wing nut 2|. A similar arrangement is provided to prevent the weight of V-block M from distorting the end I9 of the tube 3 after the tube forming operation has been completed. This arrangement comprises an adjustable screw 22 mounted in the free end of a bracket 23, which has an end thereof attached to the V-block l4. The free end of the bracket 23 lies above the V-block 3. The screw 22 is adjusted so that it will engage the top of the V-block 13 when the tube forming operation has been completed.

The jig 4 with the lamp tube 3 properly positioned on and secured thereto, and the V-blocks tube 3 andthe exhaust tube l.

rests onthe annular plate l2 and the ends 2 and tageous to elevate the side of the jig which supports the raised end iii of the tube 3 about 8 degrees. This canting of the jig is particularly advantageous in cases where the distance between the ends of the tube 3 is greater than the finally desired distance because, when theheated glass becomes plastic, gravity will cause the end-i9 of the tube 3 to move toward the end 2 of the tube, thus causing it to assume a position which will finally locate it at the desired predetermined distance from the end 2,

As mentioned above, an object of this invention fete-provide a mechanical means for bending the exhaust tube I out of the path of the end IQ of the lamp tube 3, and assume a position which- 4. will facilitate the further processing of the tube 3. The mechanism of our invention accomplishes this during the lamp tube bending operation, while the jig is canted in the manner described above.

When the tube 3 is mounted on the jig 4, the exhaust tube l is disposed in the cradle 5 of the exhaust tube bending apparatus. The temperature of the oven in which the jig and tube is disposed is sufficiently high to effect a softening of the lamp The exhaust tube bending mechanism remains stationary until the exhaust tube becomes sufliciently pliable to enable the vertical component of the weight 8 to be translated into angular motion of the cradle 5 in which the exhaust tube I is disposed, through the rotary motion of the shaft 5. The weighting of the exhaust tube'beliding mechanism is calculated to effect the withdrawal of the exhaust tube I from the path of the end l9 of the lamp tube 3 before the end l9 has moved down into position on the annular plate [2. the stop 9 is provided to exactly define the end of the path through which the cradle 5 travels and thus insures the desired disposition of the exhaust tube upon completion of the exhaust tube bending operation.

The exhaust tube bending mechanism, which is shown in detail in Figure 3, is supported by a bracket 25 which is mounted on the bottom of the annular plate I 2. The pivot shaft 6, to which the exhaust tube cradle 5 and the moment arm 1 are fixedly connected, is mounted in suitable low friction bearings to permit free movement thereof in translating the vertical component of the weighted member 8 on the outer end of themoment arm 1 into angular motion substantially paralleling the surface of the annular plate l2 of the jig 4. The upper portion of the shaft 6 is mounting in bearing 26 which, for convenience,

has been formed integral with stop 24. The shaft 6 extends through the annular plate 12 and the lower end thereof is mounted in a suitable low friction bearing, such as a lava cup 21, for example. The lava cup 21 is seated in a bearing support 28 on the outer end of the bracket 25. The bearing support 28 is provided with a threaded aperture 29 for a screw 30. The screw 30 provides a means for properly positioning the lava bearing 2'! and for adjustments thereof which may be necessary due to wear.

A collar 3| on an end of the cradle 5 serves as the means whereby the cradle 5 is fixedly connected to the shaft 6. The moment arm 1 is connected to the shaft 6 by means of a bracket 33 which has a collar 32 on one end thereof and a collar 34 at the other end thereof. The collar 32 is fixedly connected to the inner end of the connected to the arm 1 and the collar 34 is fixedly shaft 6.

Although we have shown and described the exhaust tube bending mechanism of our invention as comprising an exhaust tube cradle fixedly mounted on a pivotal shaft, it will readily be understood by those skilled in the art that if desired one may pivotally mount the exhaust tube For example, the exhaust tubewhich will not be adversely affected by operating conditions to which the mechanism may be sub- A stop 24 mounted on jected, such as the high temperature necessary to soften the exhaust tube to a pliable state, for example.

What we claim is:

1. Apparatus for bending an electric lamp exhaust tube which has been heated to a pliable state, said apparatus comprising a mounting surface; a rotatable shaft supported by said mounting surface; a cradle for said exhaust tube fixedly connected at one end thereof to said shaft; a moment arm fixedly connected at one end thereof to said shaft; and a weighted member disposed the plane thereof, said jig comprising a base member, means for positioning said lamp tube on said base member, means, upon the application of heat to the lamp tube, to bring the axis of the lamp tube into a plane, means for causing the ends of said lamp tube to be disposed a predetermined distance from each other, and apparatus for bending said exhaust tube when said tube is heated to a pliable state so that a portion thereof will lie along a line which is substantially in the plane of and radial to the lamp tube axis circle and substantially centered between the ends of said circular lamp tube.

GERALD S. QUINN.

OLIVER MANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,239,055 Sawyer Apr. 22, 1941 2,265,070 Goode Dec. 2, 1941 

